Electricity help please?

[mike31154]

If you have a humidifier attached to the ducting on your furnace (usually forced air gas furnaces), you'll see what I mean by a mechanical float switch. The line feeding this type of humidifier is plumbed right into your cold water supply, usually with a small valve fitting which pierces the pipe. Whenever the water level in the humidifier tray drops, the mechanical float valves opens sufficiently to allow the cold water supply to refill the tray. They usually use quarter inch plastic pipe similar to that used on RODI systems.

Most RO/DI unit vendors also sell mechanical float switches specifically made for that application. I don't have any photos or diagrams handy, but it's simply a matter of having a container with your top off water above the sump. This will have a line plumbed to the bottom of it using a bulkhead fitting or uniseal or even some sort of shut off valve. The line in turn is run down to the sump and to the mechanical float switch which is attached to the sump at the level you want it topped up to. Open the valve at the bottom of the top off container et voila, gravity takes over and the mechanical float shuts down the flow when the desired level is reached.